Giardiavirus internal ribosome entry site has an apparently unique mechanism of initiating translation.

ABSTRACT: Giardiavirus (GLV) utilizes an internal ribosome entry site (IRES) for translation initiation in the early branching eukaryote Giardia lamblia. Unlike most of the viral IRESs among higher eukaryotes, which localize primarily within the 5'-untranslated region (UTR), the GLV IRES comprises 253 nts of 5'UTR and the initial 264 nts in the open-reading-frame (ORF). To test if GLV IRES also functions in higher eukaryotic systems, we examined it in rabbit reticulocyte lysate (RRL) and found that it functions much less efficiently than the IRES from the Encephalomyocarditis virus (EMCV) or Cricket paralysis virus (CrPV). In contrast, both EMCV-IRES and CrPV-IRESs were inactive in transfected Giardia cells. Structure-function analysis indicated that only the stem-loop U5 from the 5'UTR and the stem

SUBMITTER: Garlapati S 

PROVIDER: S-EPMC2757703 | biostudies-literature | 2009 Oct

REPOSITORIES: biostudies-literature